/*
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 */

package com.atom.office.fc.dom4j;

import com.atom.office.fc.dom4j.tree.QNameCache;
import com.atom.office.fc.dom4j.util.SingletonStrategy;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;


/**
 * <p>
 * <code>QName</code> represents a qualified name value of an XML element or
 * attribute. It consists of a local name and a {@link Namespace}instance. This
 * object is immutable.
 * </p>
 * 
 * @author <a href="mailto:jstrachan@apache.org">James Strachan </a>
 */
public class QName implements Serializable
{
    /** The Singleton instance */
    private static SingletonStrategy singleton = null;

    static
    {
        try
        {
            String defaultSingletonClass = "com.atom.fc.dom4j.util.SimpleSingleton";
            Class clazz = null;
            try
            {
                String singletonClass = defaultSingletonClass;
                singletonClass = System.getProperty("com.atom.fc.dom4j.QName.singleton.strategy",
                    singletonClass);
                clazz = Class.forName(singletonClass);
            }
            catch(Exception exc1)
            {
                try
                {
                    String singletonClass = defaultSingletonClass;
                    clazz = Class.forName(singletonClass);
                }
                catch(Exception exc2)
                {
                }
            }
            singleton = (SingletonStrategy)clazz.newInstance();
            singleton.setSingletonClassName(QNameCache.class.getName());
        }
        catch(Exception exc3)
        {
        }
    }

    /** The local name of the element or attribute */
    private String name;

    /** The qualified name of the element or attribute */
    private String qualifiedName;

    /** The Namespace of this element or attribute */
    private transient Namespace namespace;

    /** A cached version of the hashcode for efficiency */
    private int hashCode;

    /** The document factory used for this QName if specified or null */
    private DocumentFactory documentFactory;

    public QName(String name)
    {
        this(name, Namespace.NO_NAMESPACE);
    }

    public QName(String name, Namespace namespace)
    {
        this.name = (name == null) ? "" : name;
        this.namespace = (namespace == null) ? Namespace.NO_NAMESPACE : namespace;
    }

    public QName(String name, Namespace namespace, String qualifiedName)
    {
        this.name = (name == null) ? "" : name;
        this.qualifiedName = qualifiedName;
        this.namespace = (namespace == null) ? Namespace.NO_NAMESPACE : namespace;
    }

    public static QName get(String name)
    {
        return getCache().get(name);
    }

    public static QName get(String name, Namespace namespace)
    {
        return getCache().get(name, namespace);
    }

    public static QName get(String name, String prefix, String uri)
    {
        if (((prefix == null) || (prefix.length() == 0)) && (uri == null))
        {
            return QName.get(name);
        }
        else if ((prefix == null) || (prefix.length() == 0))
        {
            return getCache().get(name, Namespace.get(uri));
        }
        else if (uri == null)
        {
            return QName.get(name);
        }
        else
        {
            return getCache().get(name, Namespace.get(prefix, uri));
        }
    }

    public static QName get(String qualifiedName, String uri)
    {
        if (uri == null)
        {
            return getCache().get(qualifiedName);
        }
        else
        {
            return getCache().get(qualifiedName, uri);
        }
    }

    public static QName get(String localName, Namespace namespace, String qualifiedName)
    {
        return getCache().get(localName, namespace, qualifiedName);
    }

    /**
     * DOCUMENT ME!
     * 
     * @return the local name
     */
    public String getName()
    {
        return name;
    }

    /**
     * DOCUMENT ME!
     * 
     * @return the qualified name in the format <code>prefix:localName</code>
     */
    public String getQualifiedName()
    {
        if (qualifiedName == null)
        {
            String prefix = getNamespacePrefix();

            if ((prefix != null) && (prefix.length() > 0))
            {
                qualifiedName = prefix + ":" + name;
            }
            else
            {
                qualifiedName = name;
            }
        }

        return qualifiedName;
    }

    /**
     * DOCUMENT ME!
     * 
     * @return the namespace of this QName
     */
    public Namespace getNamespace()
    {
        return namespace;
    }

    /**
     * DOCUMENT ME!
     * 
     * @return the namespace URI of this QName
     */
    public String getNamespacePrefix()
    {
        if (namespace == null)
        {
            return "";
        }

        return namespace.getPrefix();
    }

    /**
     * DOCUMENT ME!
     * 
     * @return the namespace URI of this QName
     */
    public String getNamespaceURI()
    {
        if (namespace == null)
        {
            return "";
        }

        return namespace.getURI();
    }

    /**
     * DOCUMENT ME!
     * 
     * @return the hash code based on the qualified name and the URI of the
     *         namespace.
     */
    public int hashCode()
    {
        if (hashCode == 0)
        {
            hashCode = getName().hashCode() ^ getNamespaceURI().hashCode();

            if (hashCode == 0)
            {
                hashCode = 0xbabe;
            }
        }

        return hashCode;
    }

    public boolean equals(Object object)
    {
        if (this == object)
        {
            return true;
        }
        else if (object instanceof QName)
        {
            QName that = (QName)object;

            // we cache hash codes so this should be quick
            if (hashCode() == that.hashCode())
            {
                return getName().equals(that.getName())
                    && getNamespaceURI().equals(that.getNamespaceURI());
            }
        }

        return false;
    }

    public String toString()
    {
        return super.toString() + " [name: " + getName() + " namespace: \"" + getNamespace()
            + "\"]";
    }

    /**
     * DOCUMENT ME!
     * 
     * @return the factory that should be used for Elements of this QName
     */
    public DocumentFactory getDocumentFactory()
    {
        return documentFactory;
    }

    public void setDocumentFactory(DocumentFactory documentFactory)
    {
        this.documentFactory = documentFactory;
    }

    private void writeObject(ObjectOutputStream out) throws IOException
    {
        // We use writeObject() and not writeUTF() to minimize space
        // This allows for writing pointers to already written strings
        out.writeObject(namespace.getPrefix());
        out.writeObject(namespace.getURI());

        out.defaultWriteObject();
    }

    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException
    {
        String prefix = (String)in.readObject();
        String uri = (String)in.readObject();

        in.defaultReadObject();

        namespace = Namespace.get(prefix, uri);
    }

    private static QNameCache getCache()
    {
        QNameCache cache = (QNameCache)singleton.instance();
        return cache;
    }
}

/*
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided that the
 * following conditions are met:
 * 
 * 1. Redistributions of source code must retain copyright statements and
 * notices. Redistributions must also contain a copy of this document.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * 3. The name "DOM4J" must not be used to endorse or promote products derived
 * from this Software without prior written permission of MetaStuff, Ltd. For
 * written permission, please contact dom4j-info@metastuff.com.
 * 
 * 4. Products derived from this Software may not be called "DOM4J" nor may
 * "DOM4J" appear in their names without prior written permission of MetaStuff,
 * Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
 * 
 * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
 * 
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 */
